Sahih al-Bukhari 5952
In-book no 5952حَدَّثَنَا مُسَدَّدٌ، حَدَّثَنَا خَالِدٌ، حَدَّثَنَا حُصَيْنٌ، عَنْ سَالِمٍ، عَنْ جَابِرٍ ـ رضى الله عنه ـ قَالَ وُلِدَ لِرَجُلٍ مِنَّا غُلاَمٌ فَسَمَّاهُ الْقَاسِمَ فَقَالُوا لاَ نَكْنِيهِ حَتَّى نَسْأَلَ النَّبِيَّ صلى الله عليه وسلم فَقَالَ " سَمُّوا بِاسْمِي، وَلاَ تَكْتَنُوا بِكُنْيَتِي ".
Narrated Jabi: A man among us begot a boy whom he named Al-Qasim. The people said, "We will not call him (i.e., the father) by that Kuniya (Abu-l-Qasim) till we ask the Prophet (ﷺ) about it. The Prophet (ﷺ) said. "Name yourselves by my name, but do not call (yourselves) by my Kuniya."